The difference is 1) sugars dissolve in water lipids don't. 2) sugars are made-up of subunits that form large polymers and lipids are not and don't form polymers. 3)Lipids store more energy than sugars hoped i helped
The generalization that all organisms are composed of cells was established through multiple observations in various kinds of animals and plants. A controlled experiment of finding cells in all the kinds of living organisms is not possible or is infeasible as it will require prior knowledge of all the kinds of organisms inhabiting Earth and the effort to catch and bring them in the controlled environment of the lab for testing.